Systematic review of prevalence studies of progressive supranuclear palsy and corticobasal syndrome

Atypical Parkinsonian Disorders

Atypical parkinsonian disorders (APD) include progressive supranuclear palsy, corticobasal degeneration, and multiple system atrophy. Identifying APD is important because they have different pathogenesis, disease course, and prognosis than Parkinson's disease (PD), and require different treatments. Therefore, when encountering patients with parkinsonism, it is of crucial importance to look for "red flags" or signs, such as impairments in higher cortical function, visuomotor system, cerebellar and other motor abnormalities including dystonia, myoclonus, and apraxia that help differentiate them from PD. Although disease-modifying therapies are not yet available, treatments targeting specific symptoms may improve the quality of life in these patients.

Geometry based prediction of tau protein sites and motifs associated with misfolding and aggregation

Recent studies of tau proteins point to specific sites or motifs along the protein related to its misfolding and aggregation propensity, which is associated with neurodegenerative diseases of structure-dependent pathology. In this manuscript we employ topology and geometry to analyze the local structure of tau proteins obtained from the Protein Data Bank. Our results show that mathematical topology/geometry of cryo-EM structures alone identify the PGGG motifs, and the PHF6(*) motifs as sites of interest and reveal a geometrical hierarchy of the PGGG motifs that differs for 3R+4R and 4R tauopathies. By employing the Local Topological Free Energy (LTE), we find that progressive supranuclear palsy (PSP) and globular glial tauopathy (GGT) have the highest LTE values around residues 302-305, which are inside the jR2R3 peptide and in the vicinity of the 301 site, experimentally associated with aggregation. By extending the LTE definition to estimate a global topological free energy, we find that the jR2R3 peptide of PSP and GGT, has in fact the lowest global topological free energy among other tauopathies. These results point to a possible correlation between the global topological free energy of parts of the protein and the LTE of specific sites.

Dysphagia Prevalence in Progressive Supranuclear Palsy: A Systematic Review and Meta-Analysis

The objective of this systematic review was to determine the prevalence of dysphagia and aspiration in people with progressive supranuclear palsy (PSP). A search of six electronic databases was performed from inception to April 2022. No context restrictions were set. All primary research comprising figures to derive a prevalence rate were included. Two independent reviewers screened search results. Data were extracted by one reviewer. Conflicts were resolved by discussion with a third reviewer. The quality of included studies was assessed using the JBI Checklist for Prevalence Studies. From 877 studies, 12 were eligible for inclusion. Dysphagia had to be confirmed using instrumental assessments, clinical swallowing evaluation, screening, and patient-reported outcome measures (PROM). A random-effects meta-analysis calculated a pooled dysphagia prevalence in 78-89% (95% CI [60.6, 89.1], [78.9, 95.0]). depending on the chosen assessment method, and a pooled aspiration prevalence of 23.5% (95% CI [14.5, 33.7]). The included studies were of moderate quality, with high risk of selection and coverage bias and low to moderate risk of measurement bias. Dysphagia is highly prevalent in a sample of participants with mostly moderately severe PSP. Aspiration occurs in a quarter of this sample and is likely to increase as the disease progresses. Given the low general prevalence of PSP, studies remain at high risk for selection bias. Prospective research should focus on the development of dysphagia in the course of PSP and its subcategories using instrumental assessment and consider all phases of swallowing. REGISTRATION: The protocol of this systematic review was registered on the International Prospective Register of Systematic Reviews (PROSPERO) in April 2021 (registration number: CRD42021245204).

"¿Cómo qué, cómo qué? cómo qué?" Single-language echolalia in a bilingual female with progressive supranuclear palsy: a case report

The case study explores bilingualism and neurodegenerative disorders, specifically progressive supranuclear palsy (PSP) with speech and language disorder (PSP-SL). It features a 78-year-old Mexican American woman who exhibits echolalia only in response to Spanish. This selective impairment suggests unevenly affected language control mechanisms despite her proficiency in both languages. Cognitive function is evaluated with neuropsychological tests; she's diagnosed with PSP-SL, depression, and anxiety. Echolalia in response to one language implies complex phonological retrieval mechanisms. Such observations prompt further inquiry into bilingual language control and processing mechanisms. The case supports evidence that bilingualism may attenuate neurodegeneration effects, suggesting better inhibitory control over disinhibited speech through enhanced executive functioning benefits.

The enigma of depression in corticobasal degeneration, a frequent but poorly understood co-morbidity

Depression is one of the most frequent neuropsychiatric symptoms in corticobasal degeneration (CBD), a rare, sporadic, and late-onset progressive neurodegenerative disorder of unknown etiology. It is clinically characterized by a levodopa-poorly responsible akinetic-rigid syndrome, apraxia, limb dystonia, cognitive, mood, behavioral, and language disorders. This 4-repeat (4R) tauopathy is morphologically featured by asymmetric frontoparietal atrophy, neuronal loss, and gliosis in cortex and subcortex including substantia nigra, ballooned/achromatic neurons with filamentous 4R tau aggregates in cortex and striatum, widespread thread-like structures, pathognomonic "astroglial plaques", "tufted astrocytes", and numerous "coiled bodies" (in astrocytes and oligodendroglia) in cerebral white matter. CBD is non-specific, as pathologically proven cases include several clinical phenotypes. Pubmed and Google Scholar were systematically analyzed until October 2023, with focus on the prevalence, clinical manifestation, neuroimaging data, and treatment options of depression in CBD. Its prevalence is about 30-40% which is more frequent than in most other atypical parkinsonian syndromes. Depression usually does not correlate with motor and other clinical parameters, suggesting different pathophysiological mechanisms. Asymmetric atrophy and hypometabolism of frontoparietal cortical areas are associated with disruption of fronto-subcortical circuits, nigrostriatal dopaminergic, and cholinergic deficiency. Since no specific neuroimaging, neuropathological, or biomarker studies of depression in CBD are available, its pathobiological mechanisms and pathogenesis are poorly understood. Antidepressive therapy may be useful, but is often poorly tolerated. Depression in CBD, like in other parkinsonian syndromes, may be related to multi-regional patterns of cerebral disturbances and complex pathogenic mechanisms that deserve further elucidation as a basis for early diagnosis and adequate treatment to improve the quality of life in this fatal disease.

Evaluation of cerebrospinal fluid alpha-synuclein seed amplification assay in PSP and CBS

Background

Seed amplification assay (SAA) testing has become an important biomarker in the diagnosis of alpha-synuclein related neurodegenerative disorders.

Objectives

To assess the rate of alpha-synuclein SAA positivity in progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS), and analyse the clinical and pathological features of SAA positive and negative cases.

Methods

106 CSF samples from clinically diagnosed PSP (n=59), CBS (n=37) and indeterminate parkinsonism cases (n=10) were analysed using alpha-synuclein SAA.

Results

Three cases (1 PSP, 2 CBS) were Multiple System Atrophy (MSA)-type SAA positive. 5/59 (8.5%) PSP cases were Parkinson's disease (PD)-type SAA positive, and these cases were older and had a shorter disease duration compared with SAA negative cases. In contrast, 9/35 (25.7%) CBS cases were PD-type SAA positive.

Conclusions

Our results suggest that PD-type seeds can be detected in PSP and CBS using a CSF alpha-synuclein SAA, and in PSP this may impact on clinical course.

Exploring the significance of caspase-cleaved tau in tauopathies and as a complementary pathology to phospho-tau in Alzheimer's disease: implications for biomarker development and therapeutic targeting

Tauopathies are neurodegenerative diseases that typically require postmortem examination for a definitive diagnosis. Detecting neurotoxic tau fragments in cerebrospinal fluid (CSF) and serum provides an opportunity for in vivo diagnosis and disease monitoring. Current assays primarily focus on total tau or phospho-tau, overlooking other post-translational modifications (PTMs). Caspase-cleaved tau is a significant component of AD neuropathological lesions, and experimental studies confirm the high neurotoxicity of these tau species. Recent evidence indicates that certain caspase-cleaved tau species, such as D13 and D402, are abundant in AD brain neurons and only show a modest degree of co-occurrence with phospho-tau, meaning caspase-truncated tau pathology is partially distinct and complementary to phospho-tau pathology. Furthermore, these caspase-cleaved tau species are nearly absent in 4-repeat tauopathies. In this review, we will discuss the significance of caspase-cleaved tau in the development of tauopathies, specifically emphasizing its role in AD. In addition, we will explore the potential of caspase-cleaved tau as a biomarker and the advantages for drug development targeting caspase-6. Developing specific and sensitive assays for caspase-cleaved tau in biofluids holds promise for improving the diagnosis and monitoring of tauopathies, providing valuable insights into disease progression and treatment efficacy.

Monash-Alfred protocol for assessment of atypical parkinsonian syndromes (MAP-APS)

Introduction

Atypical parkinsonian syndromes (APS) are rare neurodegenerative syndromes for which parkinsonism is one significant feature. APS includes progressive supranuclear palsy (PSP), multiple system atrophy (MSA) and corticobasal syndrome (CBS). The diagnosis of APS remains reliant on clinical features with no available diagnostic or prognostic biomarker. Clinical scales remain the gold standard assessment measures in clinical trials and research. The lack of standardised approach for research cohorts has contributed to shortcomings in disease understanding and limits collaboration between researchers. The primary objectives of this study are to (1) establish an assessment protocol for parkinsonian syndromes and (2) to implement it at a single site to establish the viability and utility of populating a clinical and biological databank of patients with APS.

Methods

The Monash Alfred Protocol for Assessment of APS was devised by expert consensus within a broad multidisciplinary team. Eligible patients are diagnosed as possible or probable PSP, MSA or CBS by a consultant neurologist with expertise in movement disorders. Participants will be assessed at recruitment and then annually for up to 3 years; individuals within 5 years of index symptom onset will also undergo a once-off 6-month assessment.

Ethics and dissemination

Each participant or their legally authorised representative will provide informed written consent prior to commencement of the study. Data will be stored on a locally hosted Research Electronic Data Capture database.

Trial registration number

Australian New Zealand Clinical Trials Registry (ANZCTN 12622000923763).

Association of Insulin-like Growth Factor-1 and Neurofilament Light Chain in Patients with Progressive Supranuclear Palsy

Background

Progressive supranuclear palsy (PSP) is the most common primary tauopathy. The definite diagnosis of PSP is established by histopathologic changes in the brain. There are no reliable blood-based biomarkers to aid the diagnosis of this fatal disease at an early stage. Also, the precise etiopathology of PSP and its variants is inadequately understood.

Objective

Blood-based molecules such as neurofilament light chain (NfL) and insulin-like growth factor-1 (IGF-1) are shown as important markers of neurodegenerative and aging processes, respectively. These two biomarkers have not been analyzed simultaneously in PSP patients.

Methods

To address this knowledge gap, 40 PSP patients and equal number of healthy individuals were recruited and serum levels of NfL and IGF-1 were assayed in all the study participants by enzyme-linked immunosorbent assay (ELISA). Motor and nonmotor symptoms were evaluated in PSP patients using various scales/questionnaires. Cardiac autonomic function tests were performed in a subset of patients (n = 27).

Results

A significantly high serum level of NfL (P < 0.01) and a reduced level of IGF-1 (P = 0.02) were observed in PSP patients compared to healthy controls. Besides, a negative correlation (r = -0.54, P < 0.01) between NfL and IGF-1 levels was observed in PSP patients.

Conclusion

The finding of this study reinforces the important role of blood NfL level as a potential biomarker of PSP. Further, the current study provides novel insights into the reciprocal correlation between NfL and IGF-1 in PSP patients. Combined analysis of blood levels of these two functionally relevant markers might be useful in the prediction and diagnosis of PSP.

Physiotherapy case reports on three people with progressive supranuclear palsy

Introduction

Progressive supranuclear palsy (PSP) is a neurodegenerative brain disease that affects patient's functionality and quality of life. Physiotherapy should be recommended at the time of diagnosis to slow the progression of disability and enhance the quality of life of these patients.

Clinical presentation

Here, we describe three cases of patients with PSP, outlining their motor and non-motor symptoms and examining their clinical progression with physiotherapy intervention. During the initial intervention years, a reduction in the number of falls was achieved, along with improvements in gait and balance.

Conclusion

Exercise and physiotherapy appear to be beneficial for patients with PSP by enhancing their functionality and quality of life. Controlling or reducing the number of falls should be the primary goal of any intervention for patients with PSP.

Pathomechanisms of cognitive and behavioral impairment in corticobasal degeneration

Corticobasal degeneration (CBD) is a rare, sporadic, late-onset progressive neurodegenerative disorder of unknown etiology, clinically characterized by an akinetic-rigid syndrome, behavior and personality disorders, language problems (aphasias), apraxia, executive and cognitive abnormalities and limb dystonia. The syndrome is not specific, as clinical features of pathologically proven CBD include several phenotypes. This 4-repeat (4R) tauopathy is morphologically featured by often asymmetric frontoparietal atrophy, ballooned/achromatic neurons containing filamentous 4R-tau aggregates in cortex and striatum, thread-like processes that are more widespread than in progressive supranuclear palsy (PSP), pathognomonic "astroglial plaques", and numerous inclusions in both astrocytes and oligodendroglia ("coiled bodies") in the white matter. Cognitive deficits in CBD are frequent initial presentations before onset of motor symptoms, depending on the phenotypic variant. They predominantly include executive and visuospatial dysfunction, sleep disorders and language deficits with usually preserved memory domains. Neuroimaging studies showed heterogenous locations of brain atrophy, particularly contralateral to the dominant symptoms, with disruption of striatal connections to prefrontal cortex and basal ganglia circuitry. Asymmetric hypometabolism, mainly involving frontal and parietal regions, is associated with brain cholinergic deficits, and dopaminergic nigrostriatal degeneration. Widespread alteration of cortical and subcortical structures causing heterogenous changes in various brain functional networks support the concept that CBD, similar to PSP, is a brain network disruption disorder. Putative pathogenic factors are hyperphosphorylated tau-pathology, neuroinflammation and oxidative injury, but the basic mechanisms of cognitive impairment in CBD, as in other degenerative movement disorders, are complex and deserve further elucidation as a basis for early diagnosis and adequate treatment of this fatal disorder.

Fundamental Neurochemistry Review: Copper availability as a potential therapeutic target in progressive supranuclear palsy: Insight from other neurodegenerative diseases

Since the first description of Parkinson's disease (PD) over two centuries ago, the recognition of rare types of atypical parkinsonism has introduced a spectrum of related PD-like diseases. Among these is progressive supranuclear palsy (PSP), a neurodegenerative condition that clinically differentiates through the presence of additional symptoms uncommon in PD. As with PD, the initial symptoms of PSP generally present in the sixth decade of life when the underpinning neurodegeneration is already significantly advanced. The causal trigger of neuronal cell loss in PSP is unknown and treatment options are consequently limited. However, converging lines of evidence from the distinct neurodegenerative conditions of PD and amyotrophic lateral sclerosis (ALS) are beginning to provide insights into potential commonalities in PSP pathology and opportunity for novel therapeutic intervention. These include accumulation of the high abundance cuproenzyme superoxide dismutase 1 (SOD1) in an aberrant copper-deficient state, associated evidence for altered availability of the essential micronutrient copper, and evidence for neuroprotection using compounds that can deliver available copper to the central nervous system. Herein, we discuss the existing evidence for SOD1 pathology and copper imbalance in PSP and speculate that treatments able to provide neuroprotection through manipulation of copper availability could be applicable to the treatment of PSP.

The prevalence and incidence of progressive supranuclear palsy and corticobasal syndrome: a systematic review and meta-analysis

INTRODUCTION

Progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) are progressive neurodegenerative syndromes characterised by Parkinsonism with additional features including cognitive dysfunction, falls, and oculomotor abnormalities. Understanding the epidemiology of these conditions is critical to planning for future service provision.

METHODS

We conducted a systematic review of studies reporting incidence and prevalence of CBS and PSP. A search of the PubMed and EMBASE data bases was conducted from their date of inception to 13th July 2021. Meta-analysis of studies sharing similar methodologies was carried out to generate estimated pooled prevalence and incidence.

RESULTS

We found 32 studies meeting our criteria for inclusion. There were 20 studies with data on prevalence and 12 with incidence data of PSP. Prevalence of CBS was reported in eight studies while seven studies reported incidence. Reported estimates of prevalence for PSP ranged from 1.00 (0.9-1.1) to 18 (8-28) per 100,000 while prevalence rates for CBS ranged from 0.83 (0.1-3.0) to 25 (0-59). Incidence rates for PSP and CBS respectively ranged from 0.16 (0.07-0.39) to 2.6 per 100,000 person-years and 0.03 (0-0.18) to 0.8 (0.4-1.3) per 100,000 person-years. A random effects model meta-analysis of studies with similar methodologies yielded a pooled prevalence estimate for PSP of 6.92 (4.33-11.06, I2 = 89%, τ2 = 0.3907) and 3.91 (2.03-7.51, I2 = 72%, τ2 = 0.2573) per 100,000 for CBS.

CONCLUSION

Studies of the epidemiology of PSP and CBS report highly heterogeneous findings. There is a need for further studies using rigorous phenotyping and the most recent diagnostic criteria to understand the true burden of these conditions.

Low clinical sensitivity and unexpectedly high incidence for neuropathologically diagnosed progressive supranuclear palsy

The objective of this study was to determine the prevalence, incidence, and clinical diagnostic accuracy for neuropathologically diagnosed progressive supranuclear palsy (PSP) with data from a longitudinal clinicopathological study using Rainwater criteria to define neuropathological PSP. Of 954 autopsy cases, 101 met Rainwater criteria for the neuropathologic diagnosis of PSP. Of these, 87 were termed clinicopathological PSP as they also had either dementia or parkinsonism or both. The prevalence of clinicopathologically defined PSP subjects in the entire autopsy dataset was 9.1%, while the incidence rate was estimated at 780 per 100 000 persons per year, roughly 50-fold greater than most previous clinically determined PSP incidence estimates. A clinical diagnosis of PSP was 99.6% specific but only 9.2% sensitive based on first examination, and 99.3% specific and 20.7% sensitive based on the final clinical exam. Of the clinicopathologically defined PSP cases, 35/87 (∼40%) had no form of parkinsonism at first assessment, while this decreased to 18/83 (21.7%) at final assessment. Our study confirms a high specificity but low sensitivity for the clinical diagnosis of PSP. The low clinical sensitivity for PSP is likely primarily responsible for previous underestimates of the PSP population incidence rate.

Global Epidemiology of Movement Disorders: Rare or Underdiagnosed?

In this manuscript, we review the epidemiology of movement disorders including Parkinson's disease (PD), atypical parkinsonism, essential tremor, dystonia, functional movement disorders, tic disorders, chorea, and ataxias. We emphasize age-, sex-, and geography-based incidence and prevalence, as well as notable trends including the rising incidence and prevalence of PD. Given the growing global interest in refining clinical diagnostic skills in recognizing movement disorders, we highlight some key epidemiological findings that may be of interest to clinicians and health systems tasked with diagnosing and managing the health of patients with movement disorders.

Neurologic music therapy combined with EEG-tDCS for upper motor extremity performance in patients with corticobasal syndrome: Study protocol for a novel approach

BACKGROUND

Corticobasal syndrome (CBS) is an atypical parkinsonian disorder that involves degeneration of brain regions associated with motor coordination and sensory processing. Combining transcranial direct current stimulation (tDCS) with rehabilitation training has been shown to improve upper-limb performance in other disease models. Here, we describe the protocol investigating whether tDCS with neurologic music therapy (NMT) (patterned sensory enhancement and therapeutic instrumental music performance) enhances functional arm/hand performance in individuals with CBS.

METHODS

Study participants are randomly assigned to six 30-min sessions (twice per week for 3 weeks) of NMT + either sham tDCS or active tDCS. We aim to stimulate the frontoparietal cortex, which is associated with movement execution/coordination and sensory processing. The hemisphere contralateral to the more affected arm is stimulated (total stimulation current of 2 mA from 5 dime-sized electrodes). Individualized NMT sessions designed to exercise the upper limb are provided. Participants undergo gross/fine motor, cognitive and emotional assessments at baseline and follow-up (one month after the final session). To investigate the immediate effects of tDCS and NMT training, gross /fine motor, affective level, and kinematic parameter measurements using motion sensors are collected before and after each session. Electroencephalography is used to collect electrical neurophysiological responses before, during, and after tDCS+NMT sessions. The study participants, neurologic music therapist and outcome assessor are blinded to whether participants are in the sham or active tDCS group.

CONCLUSION

This noninvasive and patient-centered clinical trial for CBS may provide insight into rehabilitation options that are sorely lacking in this population.

The many faces of globular glial tauopathy: A clinical and imaging study

BACKGROUND

Globular glial tauopathy (GGT) has been associated with frontotemporal dementia syndromes; little is known about the clinical and imaging characteristics of GGT and how they differ from other non-globular glial 4-repeat tauopathies (N4GT) such as progressive supranuclear palsy (PSP) or corticobasal degeneration (CBD).

METHODS

For this case-control study the Mayo Clinic brain banks were queried for all cases with an autopsy-confirmed diagnosis of GGT between 1 January 2011 and 31 October 2021. Fifty patients with N4GT (30 PSP, 20 CBD) were prospectively recruited and followed by the Neurodegenerative Research Group at Mayo Clinic, Minnesota. Magnetic resonance imaging was used to characterize patterns of gray/white matter atrophy, MR-parkinsonism index, midbrain volume, and white matter hyperintensities.¹⁸ F-Fluorodeoxyglucose-, ¹¹ C Pittsburg compound-, and ¹⁸ F-flortaucipir-positron emission tomography scans were reviewed.

RESULTS

Twelve patients with GGT were identified: 83% were women compared to 42% in NG4T (p = 0.02) with median age at death 76.5 years (range: 55-87). The most frequent clinical features were eye movement abnormalities, parkinsonism, behavioral changes followed by pyramidal tract signs and motor speech abnormalities. Lower motor neuron involvement was present in 17% and distinguished GGT from NG4T (p = 0.035). Primary progressive apraxia of speech was the most frequent initial diagnosis (25%); 50% had a Parkinson-plus syndrome before death. Most GGT patients had asymmetric frontotemporal atrophy with matching hypometabolism. GGT patients had more gray matter atrophy in temporal lobes, normal MR-parkinsonism index, and larger midbrain volumes.

CONCLUSIONS

Female sex, lower motor neuron involvement in the context of a frontotemporal dementia syndrome, and asymmetric brain atrophy with preserved midbrain might be suggestive of underlying GGT.

Epidemiology of Progressive Supranuclear Palsy: Real World Data from the Second Largest Health Plan in Israel

Progressive supranuclear palsy (PSP) is a rare and fatal neurodegenerative movement disorder and no disease modifying therapy (DMT) is currently available. This study aims to assess the epidemiology of PSP in Israel and to describe its clinical features. This retrospective analysis identified patients with PSP between 2000 and 2018 over the age of 40 years at first diagnosis (index date). We identified 209 patients with ≥1 diagnosis of PSP. Of those, 88 patients satisfied the inclusion criteria with a mean age at diagnosis of 72 years (SD = 8) and 53% were female. The 2018 prevalence and incidence rates were 5.3 and 1 per 100,000 persons, respectively. Median survival time was 4.9 years (95% CI 3.6-6.1) and median time from initial symptom to diagnosis was 4.2 years. The most common misdiagnoses were Parkinson's disease, cognitive disorder and depression. The present study demonstrates that the clinic-epidemiological features of PSP in Israel are similar to PSP worldwide. In light of PSP's rarity, investigation of PSP cohorts in different countries may create a proper platform for upcoming DMT trials.